Apparatus for determining salinity variations in shales

ABSTRACT

An apparatus for determining salinity variations in shales, automatically or semiautomatically, to substantially continuously measure the variations of the salinity of water from different elevations in a well.

,Jl I Unite States Patent [111 AM [72] Inventor Harold L. Overtoln [56]References Cited g ll87llyvgili lpermg Creelk, llllarrls County, UNITEDSTATES PATENTS [2|] App No E 2,330,394 9/1943 Stuart 324/30 [22] Filed g2 1970 2,938,708 5/l960 Arps l75/50 5] a e Dec 1971 2,266,586 l2/l94lBranum 73/l53 2,749,748 6/1956 Slohod 73/153 2,692,755 l0/l954 Nowak73/l53 [54] APPARATUS FOR DETERMINING SALHNITY Primary Examiner MichaelJ, Lynch VAEIIATIONS IN SHAFliJES Attorney-Pravel, Wilson & Matthews l0laims, 1 Drawing g.

[52] US. Cl. gallgglioflgg ABSTRACT: An apparatus for determiningsalinity variations [5 I] Int Cl 6 27/00 in shales, automatically orsemiautomatically, to substantially [50] Fieud 30. continuously measurethe variations of the salinity of water M51 5 23/230 from differentelevatlonsln awell.

APPARATUS FOR DETERMINING SALINITY VARIATIONS IN SI-IALES BACKGROUND OFTHE INVENTION SUMMARY OF THE INVENTION The present invention relates toa new and improved apparatus for obtaining the measurements of salinityvariations of water at different elevations in a well for carrying outthe process of said application Ser. No. 879,147, automatically orsemiautomatically, to thereby facilitate the obtaining of suchmeasurements as the shale samples become available during the drillingofthe well.

BRIEF DESCRIPTION OF THE DRAWING The figure of the drawing illustratesschematically the apparatus of this invention for the automatic orsemiautomatic determination of salinity variations in shale cuttingsobtained from different elevations in a well bore during the drillingthereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus of this inventionincludes a conventional rotary kiln A which is mounted on any suitablesupport for rotation and which is rotated by any suitable power meanssuch as an electric motor therewith. The kiln or grinding means A ispreferably divided into three sections, l1, l2 and 14. Sections I1 and12 are separated by a wire grating 15 which has openings therethrough inthe same manner as a screen or hardware cloth, preferably of aboutone-eighth inch in size. The sections 12 and 14 are separated by asimilar wire grating 16 which has smaller openings than the wire grating15, and preferably the openings are approximately one-sixteenth inch insize. The final section 14 has a wire mesh screen 18, preferably ofabout 60 mesh so as to permit a predetermined particle size to bedischarged from the grinding kiln A, as will be more evidenthereinafter. Each of the sections has a plurality of grinding ballstherein of different sizes, withthe section II having balls 19 of aboutone-half inch in diameter with section 12 having balls 21 of aboutone-eighth inch in diameter. Balls 19, 20 and 21 are preferably formedof steel, but they may be formed of any other suitable material which ishard enough to accomplish a pulverizing or grinding of the shale whichis introduced into the kiln A to a powder which is capable of beingdischarged ultimately through the screen 18. A hopper 22 of conventionalconstruction is disposed at the upper end of the kiln A for receivingdamp-washed shale cuttings in a prescribed quantity from a particularelevation in a well which is being drilled, The cuttings may come from apredetermined range within the well, and the quantity preferably isgreat enough for each batch which is introduced through the hopper 22into the kiln A to provide the necessary cuttings for a series ofmeasurements with the apparatus of this invention, as will be moreevident hereinafter.

To dry the cuttings as they are being pulverized in the kiln me ype ofheating means is provided in conjunction with the rotating cylinder 17,such heating means preferably being electrical heating elements 23,which surround the cylinder 17 and thereby provide relatively uniformheating for vaporizing any moisture with the cuttings as they passthrough the unit A. A measuring apparatus B which includes a measuringpan 24 is disposed so as to receive the powdered shale from the kiln A.In a typical example, the batch of shale cuttings introduced at thehopper 22 from a particular elevation or range of elevation in the wellbeing drilled may be about 200 grams, and the measuring pan 24 would besuitable for receiving about 1 gram, or maybe 10 grams, depending on thesize of the other equipment being used therewith. The measuring device Bis conventional in that it has a pivoted balance arm 25, with anadjustable weight 26 on one end and the measuring pan 24 on the otherend. The balance bar 25 is balanced about a fulcrum 27 so that the arm25 may tilt about the fulcrum 27 as the pivoting point, with the extentof tipping depending upon the extent of balance between the weight 26and the pan 24 with its contents.

At the left-hand end of the balance arm 25, below the pan 24, a relay orswitch 30 is disposed for engagement by a projection 25a on the arm 25.The switch 30 is normally held open by a spring or other suitable means,but when the measuring pan 24 has received a predetermined quantity ofpowder from the kiln A, so as to substantially balance the arm 25 on thefulcrum 27, the switch 30 is closed to activate an electrical circuit,as will be explained.

The electrical circuit which has the electrical switch or relay 30 in itincludes a power source such as a battery 31, a motor 32, and anindicator light 33. Thus, when the switch 30 is closed, power issupplied to the motor 32 for operating same. The motor 32 is connectedin any conventional manner to an eccentrically mounted operating rod 34which is mounted eccentrically on a rotatable wheel or disc 35 which isschematically illustrated in the drawing. Thus, the rotation of the disc35 causes the rod 34 to move in a circular path at its lower end andthereby to move longitudinally or vertically at its upper end. When theupper end of the rod 34 engages the lower part of the pan 24, it causesit to pivot about its pivotal mounting 240 so as to cause the left-handend of the pan 24 to move downwardly and thereby tip the pan 24 to aninclined position, causing the powder or other contents in the pan 24 tobe discharged therefrom into a hopper 35.

The hopper 35 discharges the measured quantity of the shale powder intoa mixing unit C which has a tank 36 with an open upper end, and withoutlet pipes 360 and 36b at its lower end. The flow of fluid out of thetank 36 through the outlet 36a is controlled by a valve 37 whichpreferably is electrically actuated, although it may be a manuallyoperated valve. The outlet tube or pipe 36b is controlled by a valve 38which'is likewise preferably electrically operated. but which may alsobe manually controlled.

Simultaneously, with the introduction of the powder from the measuringtray 24 into the hopper 35 and thus into the mixing unit C, water,preferably distilled water, is introduced from a reservoir 40 through aninlet tube 40a. For controlling the quantity of waterintroduced into themixing unit C for each predetermined quantity of the shale powder, avalve 41 is disposed in the line 40a, and it is either electrically ormanually controlled. For example, the valve 41 may be in the sameelectrical circuit with the battery 31 and may be operated when theswitch 30 is closed so as to be open for discharging water into the tank36 while the powder from the tray 24 is being dumped into the tank 36.Equal weights of water and powder are discharged into the mixing unit 36for each measurement.

A stirring means such as stirring paddles 42 are disposed in the mixingunit C at the lower portion of the tank 36, or at any other suitablelocation therein, and such mixing blades 42 are electrically operatedthrough an electrical motor 42a which is also preferably in theelectrical circuit; with the battery 3! so that the rotor mixer 42operates when the switch 30 is closed. However, the rotor 42 continuesits operation for a predetermined time, so the motor 420 includes atimer for operating after it has been turned on to allow it to operateuntil an adequate mixing of the water and the powder has beenaccomplished in the unit C. It will be understood that the rotor 42 maybe included in a separate circuit from the battery 31 and the switch 30if desired, in which case the actuation of the rotor 42 may be handledby an operator when the powder and the water are being introduced intothe chamber 36. Both of the valves 37 and 38 are closed when mixing thepowder and the water in the tank or chamber 36. A thermometer 36a isdisposed in the tank 36 so as to obtain a temperature reading of theslurry so that suitable temperature corrections may be made in theultimate reading if they are necessary.

To obtain a resistivity measurement of the slurry within the mixing unitC, the valve 37 is opened by the operator actuating the valve 37 orbyany suitable automatic control. When the valve 37 is open, itcommunicates the outlet 360 with a tube 43 which leads to another tube43a and a vacuum pump 44. A control valve 45 is provided at the end ofthe line 43 for a purpose to be hereinafter explained. The slurry whichis drawn into the tube 43 by the operation of the vacuum pump 44contacts the electrodes 46a and 46b which are connected to a resistivitymeter 46 of conventional construction which provides a resistivityreading for the slurry. After the sample has been drawn into the tube43, the valve 37 is closed. Thereafter, the valve 38 is opened by theoperator or by an electrical circuit automatically so as to dischargethe remainder of the slurry within the mixing unit C, through the outlet36b to a discharge tube 47. The tube 47 is connected with a three'wayvalve 48 which has one of its openings connected to a tube 480 leadingto a source of gas under pressure such as nitrogen. The tube 48a isclosed when the valve 38 is open so that the slurry passes through thevalve 48 and is discharged through the line 48b into a slurry filtrationcell D which includes a chamber or tank 50 with a removable cover 50a. Afilter paper or other filtering device 51 is located within the chamber50 of the cell D so that the slurry may be filtered to leave the solidson the filter paper 51 and to force the liquid or filtrate through thefilter paper 51 and to force the liquid or filtrate through the filterpaper 51 into a tube 52 which discharges below the filter paper 51. Itshould be noted that after the charge of slurry from the mixing unit Chas passed into the cell D, the valve 48 is rotated electrically ormanually so as to connect the pipe 480 to the source of gas underpressure such as nitrogen which then discharges its gas through thevalve 48 and the line 48b to the area above the liquid slurry in thecell D. Such pressure acts to force the fluid within the slurry throughthe filter paper 51 so that the filtration progresses rapidly. lt willbeunderstood that the filter paper 51 is supported by any type offoraminous or perforated support so that the paper itself does not getforced downwardly and therefore is not ruptured during the applicationof the pressure thereto. After a sufi'icient pressure has developedwithin the cell D, the valve 48 is returned to the position shown in thedrawing so as to close off the supply of pressure to the cell D. Thevalve 38 is closed at that point or prior thereto after havingdischarged its quantity of slurry and to prepare it for receiving thenext measured quantity of slurry within the chamber 36.

The tube 52 leads to a vertical pipette 53 so that the filtrate passestherethrough and so that the resisitivity measurement of the filtratecan be obtained using electrodes 54a and 54b together with aconventional resistivity meter 54. Such reading is correlated with theresistivity reading of the slurry obtained at the meter 46 for eachelevation for which a sample is measured and for each of themeasurements for the respective elevations from which shale cuttingsamples are utilized in the apparatus of this invention. An electricalsignal light 55 may be incorporated with the pipette 53 to indicate tothe operator that there is sufficient filtrate liquid within the pipette43 for a reading on the resistivity meter 54. The filtrate is passedfrom the pipette 53 to a discharge tube or pipe 56 which leads into asodium ion potential apparatus 60 of any conventional construction. Anexample of such construction is illustrated in said copendingapplication, Ser. No. 879,147. Thus, there is a reference electrode 600and a sodium ion electrode 60b in the filtrate which serves as theelectrolyte, the upper level of which is indicated at 61 in the tank 60.Such upper level 61 may be indicated by a suitable signal device 62 sothat the operator will know when to take a reading on the potentiometer65 to obtain the sodium ion potential or potential difference readingfor the filtrate. The sodium ion potentiometer may have any suitablemeans for discharging the filtrate therefrom such as a valve 64 whichagain may be electrically or mechanically operated so that new filtratesamples are measured for the difierent elevations and for successivemeasurements at a particular elevation.

It should be noted that after each measurement of the slurry in the tube43, it is desirable to flush such tube 43 with distilled water and forthis purpose, the valve 45 may be opened, together with the valve 37 soas to wash the tube 43 with the distilled water and to remove the slurrytherefrom. The water which is used for the flushing may be dumped priorto the insertion of the next quantity of powder into the tank 36, whereit may be utilized as a part of such slurry since it is a relativelysmall amount and has a negligible effect upon the overall quantitiesbeing handled.

In addition, or in place of, the sodium ion electrode 60b, potassiumion, calcium ion and magnesium ion electrodes may be mounted inside thevessel 60 for the semiautomatic measurement of the potential differencesof the filtrate with respect to such ions.

In the use or operation of the apparatus of this invention, a quantityof shale cuttings which has been obtained from a particular elevation ora range of elevation in a well which is being drilled, is initiallywashed and when in the damp-washed condition, such cuttings areintroduced into the hopper 22. The motor 10 is operating at that timeand it continues to operate so as to rotate the kiln A to pulverizc theshale cuttings to a powder which is discharged through the screen 18onto the measuring pan or tray 24. The powder is discharged from thekiln A until a predetermined quantity is in the pan 24 so as tocounterbalance the weight 26 and close the switch 30. When the switch 30closes, the motor 10 may be stopped temporarily through any suitableelectrical controls (not shown) so that further discharge of powder fromthe kiln A is discontinued until the pan 24 has been emptied.Alternatively, the motor 10 may continue to operate the kiln A, but thepowder from the kiln A may be diverted from the pan 24 by any suitableknown means.

Upon closing of the switch 30, the motor 32 operates the rotor 35 tomove the operating arm 34 upwardly to cause the pan 24 to tilt about itspivot 24a and to thereby dump the measured quantity therefrom into thehopper 35 and then into the mixing unit C. Substantially simultaneouslywith such dumping of the powder, or at a time in close proximitythereto, water in an equal weight to the powder is discharged from thereservoir 40 into the mixing unit C where the water and the powder aremixed together with the rotating blade or rotor 42 to form a slurry. Thevalves 37 and 38 are closed during such mixing operation.

The valve 37 is opened and the vacuum pump 44 is operated with the valve45 closed so as to draw a small quantity of the slurry into the tube 43for obtaining a resistivity measurement on the meter 46 with respect tothe slurry. Thereafter, the valve 37 is closed and the vacuum pump 44 isstopped. The valve 38 is then opened, and with three-way valve 48 in theposition to discharge into the cell D, the slurry flows from the tank 36through the pipe 47 and the line 48b into the cell D. After all of theslurry has been discharged from the tank 36 into the cell D the valve 38is closed and the valve 48 is rotated to then introduce the compressedgas from the line 48a into the cell D which facilitates the filtrationthrough the filter paper or other filter medium 51. It should be notedthat when a sufficient quantity of the solids collect on the filterpaper or filter medium 51 occurs, the cell compartment or tank 50 isopened by removing the top 50a so that the solids can be discharged orremoved together with the filter paper 51. The filter paper 51 wouldthen be replaced with a clean filter paper.

The filtrate which passes through the filter paper 51 passes into thepipette 53 so that a resistivity measurement is obtained on the meter54' for such filtrate. Also, the filtrate passes into the potentiometertank 60 so as to obtain a measurement of the potential differencebetween the standard reference passes into the potentiometer tank 60 soas to obtain a measurement of the potential difference between thestandard reference electrode and the sodium ion electrode. or such otherelectrode as may be present therein. with the filtrate serving as theelectrolyte. The potential difference is indicated on the potentiometer65. The fluid in the tank 60 is discharged through the valve 64 or isotherwise removed so as to receive the next filtrate sample formeasurement: Thus, it can be seen that the apparatus of this inventionprovides an automatic, or semiautomatic, means for obtainingmeasurements with respect to the salinity conditions of water havingsalt therewith which is obtained from different elevations in a well. inother words. the water or filtrate which is actually measured in thepipette 53 and in the potentiometer tank 60 has salt which has beenpicked up from the shale by having been mixed therewith in the mixingunit C. The variations in the salinity conditions at differentelevations in a well are significant as pointed out heretofore inconnection with said patent application Ser. No. 879,147, and suchinformation can be plotted with respect to the elevation in the well soas to furnish indications of overpressure areas in a well. as well asother infonnation which is of value during the drilling of a well.

The foregoing disclosure and description of the invention areillustrative and explanatory thereof, and various changes in the size.shape, and materials as well as in the details of the illustratedconstruction may be made without departing from the spirit of theinvention.

lclaim:

1. An apparatus for substantially continuously measuring the salinityvariations of shale samples from a well, comprismg:

grinding means for grinding damp-washed shale cuttings received from awell during the drilling thereof to grind said cuttings to a powder ofpredetermined particle size;

a measuring device disposed to receive the powder discharged from saidgrinding means and to measure and discharge predetermined quantitiestherefrom a mixing unit adapted to receive said predetermined quantitiesof powder discharged from said measuring device;

means for introducing a measured quantity of water into said mixing unitfor each predetermined quantity of powder to form a slurry and means fordischarging the slurry from the mixing unit; introduced into said mixingunit;

said mixing unit including means for mixing each measured quantity ofwater and predetermined quantity of powder to form a slurry and meansfor discharging the slurry from the mixing unit;

a slurry-filtering cell adapted to receive the slurry from said mixingunit and filter same to produce a filtrate;

means for removing said filtrate from said filtering cell; and

means for making a measurement indicative of the salinity of saidfiltrate.

2. The apparatus set forth in claim ll. including:

heating means with said grinding means for heating said shale cuttingsas they are being ground to essentially dry same.

3. The apparatus set forth in claim ll, including:

means for drawing ofi a portion of said slurry from said mixing unit;and

means for measuring the resistivity of each said portion of the slurrywithdrawn from said mixing unit.

4. The apparatus set forth in claim ll, wherein said means for making ameasurement indicative of the salinity of said filtrate includes:

means for measuring the resistivity of said filtrate 5. The apparatusset forth in claim 2, wherein said means for making a measurementindicative of the salinity of said filtrate includes:

means for measuring the resistivity of said filtrate.

6. The apparatus set forth in claim U, wherein said means for making ameasurement indicative of the salinity of said filtrate includes: I

means for measuring the resistivity of said filtrate; and

means for measuring the electrical potential difference between a sodiumion electrode and a reference electrode with said filtrate present asthe electrolyte.

7. The apparatus set forth in claim 1, wherein:

said grinding apparatus has a final screen of approximately 60 meshthrough which said powder therefrom passes; and

each said measured quantity of water and each said predeterminedquantity of said powder introduced into said mixing unit are equal inweight.

8. The apparatus set forth in claim 1, wherein said grinding meanscomprises:

a rotatable kiln formed in a plurality of sections separated by gratinghaving progressively smaller holes, and with each section havinggrinding balls therein which are progressively smaller from the inlet tothe outlet thereof.

9. The apparatus set forth in claim 1, wherein said mixing unitincludes:

a vessel having a stirring means therein for agitation of the liquid inthe vessel; and

valve means for controlling the discharge of the slurry from saidvessel. 10. The apparatus set forth in claim 1, including: means forapplying fluid pressure to said slurry in said slurry filtering cell forforce filtering same.

=l 4 ll= ll

2. The apparatus set forth in claim 1, including: heating means withsaid grinding means for heating said shale cuttings as they are beingground to essentially dry same.
 3. The apparatus set forth in claim 1,including: means for drawing off a portion of said slurry from saidmixing unit; and means for measuring the resistivity of each saidportion of the slurry withdrawn from said mixing unit.
 4. The apparatusset forth in claim 1, wherein said means for making a measurementindicative of the salinity of said filtrate includes: means formeasuring the resistivity of said filtrate.
 5. The apparatus set forthin claim 2, wherein said means for making a measurement indicative ofthe salinity of said filtrate includes: means for measuring theresistivity of said filtrate.
 6. The apparatus set forth in claim 1,wherein said means for making a measurement indicative of the salinityof said filtrate includes: means for measuring the resistivity of saidfiltrate; and means for measuring the electrical potential differencebetween a sodium ion electrode and a reference electrode with saidfiltrate present as the electrolyte.
 7. The apparatus set forth in claim1, wherein: said grinding apparatus has a final screen of approximately60 mesh through which said powder therefrom passes; and each saidmeasured quantity of water and each said predetermined quantity of saidpowder introduced into said mixing unit are equal in weight.
 8. Theapparatus set forth in claim 1, wherein said grinding means comprises: arotatable kiln formed in a plurality of sections separated by gratinghaving progressively smaller holes, and with each section havinggrinding balls therein which are progressively smaller from the inlet tothe outlet thereof.
 9. The apparatus set forth in claim 1, wherein saidmixing unit includes: a vessel having a stirring means therein foragitation of the liquid in the vessel; and valve means for controllingthe discharge of the slurry from said vessel.
 10. The apparatus setforth in claim 1, including: means for applying fluid pressure to saidslurry in said slurry filtering cell for force filtering same.